Process for the chemical decomposition of halogenated organic compounds

ABSTRACT

PCT No. PCT/EP93/03609 Sec. 371 Date Jun. 12, 1995 Sec. 102(e) Date Jun. 12, 1995 PCT Filed Dec. 20, 1993 PCT Pub. No. WO94/14504 PCT Pub. Date Jul. 7, 1994Halogenated contaminants are decomposed in a fluid and solid by reacting such matrix with a reagent composed of a non-alkali metal, a polyalkyleneglycol/or NixolensR and a hydroxide/or alcoholate. Further, this reagent combined with certain solid carriers forms an immobilized decontamination bed to remove halogenated contaminants continuously from a fluid.

The present invention relates to a process for the decomposition ofhazardous halogen-containing organic compounds, such as polychlorinatedbiphenyls.

Numerous halogenated organic compounds, for example, PolychlorinatedDibenzo-p-dioxins (PCDDs), polychlorinated Dibenzofurans (PCDFs),Polychlorinated Byphenyls (PCBs), Dichlorodiphenyltrichloroethane (DDT),2, 4, 5 trichlorophenol and polyhalogenated alkylbenzene etc., posedefinite hazards to the environment and public health. A number of themare resistant to the environmental degradation and remain in hazardousforms for many years.

During the past decade, several methods of disposing of halogenatedorganic compounds have been proposed, such as incineration, a "secure"landfill and hydrothermal decomposition. However, it has been found thatthe disposal of such toxic halogenated contaminants with these methodsis not satisfactory, especially on a large scale.

Various chemical processes for decomposing halogenated organic compoundshave also been developed. Pytlewski and Smith in their U.S. Pat. No.4,337,368 and U.S. Pat. No. 4,326,090, respectively demonstrated thatpolyhalogenated organic compounds were found to be decomposed by thereaction with a preformed organo-sodium reagent, such as sodiumnaphthalenide, NaPEG. In these cases, the use of metallic sodium metalrequires special handling procedures and specialized equipment, andtrace amount of water must be eliminated so as to avoid dangerous sidereactions.

It has been further proposed by Brunelle of General Electric in U.S.Pat. Nos. 4,351,718 and 4,353,793 that removal of the polychlorinatedaromatic hydrocarbon dissolved in an organic solvent, such astransformer oil, can be accomplished by treating the contaminatedsolution with a mixture of polyethyleneglycol or monocappedpolyalkyleneglycol alkyl ether and an alkali metal hydroxide. It hasbeen found that such reactions require extended periods of time toreduce the concentration of halogenated contaminants such as PCBs, to agenerally acceptable level.

Also, it has been proposed by Peterson of Niagara Mohawk PowerCorporation in U.S. Pat. No. 4,532,028 to reduce the level ofhalogenated aromatics in a hydrocarbon stream by the treatment with analkaline reactant in a sulfoxide solvent. This process involves thepurification step to remove the sulfoxides solvent after decontaminationwhere the resulting decontaminated fluid will be reused.

In our U.S. Pat. No. 4,632,742 and Eur. Pat. No. 0,118,858, Tundodisclosed a method for the decomposition of halogenated organiccompounds by a reagent which consists of (a) polyethyleneglycol,Nixolens®, an alcohol or polyhydroxy compounds, (b) a base, such asalkali or alkaline earth carbonate and bicarbonate, and (c) an oxidizingagent, such as Na₂ O₂ and BaO₂, or a source of radicals in the absenceof oxygen. This method is applicable to the decontamination of mineraloil, soil and various porous surfaces. But the use of sodium peroxide,or other oxidizing agents and the source of free radicals pose potentialexplosion and fire hazards involved in their operation. Also, this canbe prohibitively expensive because of the cost of peroxide.

Further, in our U.S. Pat. No. 4,839,042 and Eur Pat. No. 0,135,043Tumiatti et al described a continuous decontamination process with adehalogenating bed, which is composed of a polyethylene glycol or acopolymer of various alkene oxides in a certain proportion and an alkalior alkaline earth metal alcoholate, which are adsorbed on certain solidcarriers. However, this process was found to require a large amount ofreagents and extended periods of time to reduce the concentration ofhalogenated contaminants such as PCBs, to a generally acceptable level.

The continued efforts to improve our previous patented methods fordecontamination of halogenated organic compounds by enhancing itsefficiency, reducing decontamination time, operative cost and potentialhazards involved in the operation, and improving the recovery ofsubstantial fractions of functional matrix, have led to the developmentof the present invention.

The present invention provides a process for removing halogenatedorganic compound from a contaminated fluid and solid matrix. Forexample, the present invention can be applied to remove polychlorinatedbiphenyls (PCB) from contaminated transformer oils, e.g. refinedasphaltic-base mineral oils, or contaminated heat exchange oils, e.g.hydrogenated terphenyls etc., and the reuse of such fluids can beaccomplished very easily after hazardous substances are scavenged fromuseful materials with the decomposition process of the invention.

It has now been found that halogenated organic compounds can bedecomposed rapidly and completely with a reagent consisting of anon-alkali metal, a polyalkyleneglycol/or a Nixolens® and a hydroxide/oran alcoholate. This decomposition reagent overcomes the aforementioneddeficiencies of the prior art methods, and gives more effective resultsthan those obtained by using our previous art methods with a reagentproduced from an oxidizing agent or a source of radicals.

Non-alkali metals suitable for practicing the present invention arealuminium, iron, magnesium, manganese, nickel, palladium, silicon,titanium and zinc etc. It is suggested to use some specifiedcombinations between these metals such as a mixture of aluminium andtitanium. Of these metals, aluminium is particularly preferred metal dueto its high reactivity and relatively low cost.

The polyalkyleneglycol which can be used in the practice of the presentinvention, has the general formula ##STR1## wherein

X is >2 and n is an integer of 1 to 500; R may be hydrogen, a straightor branched-chain C₁ -C₂₀ alkyl group, an aralkyl or an acyl group; R₁and R₂ which can be the same or different between each other representhydrogen, straight or branched-chain alkyl group, possibly substitutedC₅ -C₈ cycloalkyl or aryl group.

In addition, Nixolens®, a series of random copolymers of various alkeneoxides in different proportions, which is distributed by the AuschemCompany of Milano, Italy, is proposed to use in carrying out the presentinvention because of its high chemicals activities and physicalcharacters. Nixolens®, a common industrial lubricant oil, includesNixolens®-NS, Nixolens®-VD and Nixolens®-SL. Of them, the preferred isNixolens®-VS, such as VS-13, VS-40 and VS-2600, which contain a lowpercentage of propylene oxide monomers and a relatively high percentageof ethylene oxide monomers.

The hydroxide and alcoholate refer to alkali, alkaline-earth metalhydroxide and alkali and alkaline-earth metal C₂ -C₆ alcoholate.

Interestingly, when a polyalkyleneglycol/or a copolymer of variousalkene oxides, having an average molecular weight more than 6000, iscombined with a non-alkali metal and a hydroxide/or an alcoholate as adecontamination reagent, a very effective elimination result isobtained, especially for lower halogen-content contaminants, such as PCBAroclor 1242, 1254 and numerous of halogenated alkylbenzenes.

It has been determined in practice that the mole ratio of polyglycol/orNixolens® to halogen is from 1:1 to 30:1, and the mole ratio ofhydroxide/or alcoholate to halogen ranges from 10:1 to 200:1. At thismole ratio, the concentration of the non-alkali metal in the reactionmixture, which consists of the decomposition reagent and contaminatedmatrix, preferably ranges from about 0.02% to 5% by weight.Surprisingly, the concentration of the non-alkali metal from 0.1% to 2%by weight within the reaction mixture is sufficient to give complete andquick elimination. Specially, when the reagent of the present inventionis used to decompose halogenated organic compounds in contaminated solidmatrix such as sludge, a relatively large amount of polyglycol/orNixolens® is employed to serve as both roles of the solvent and thereagent. In general, the amount of the reagent depends upon the type andamount of halide contaminants present.

The reaction temperature can range from about room temperature to 200°C., whereas the temperature in the range of between 70° C. to 120° C. ispreferred. The temperature can vary by depending on the nature ofvarious decomposition reagents and the type and amount of halogenatedorganic compounds to be treated.

The reagent proposed here can be directly mixed with the contaminatedfluid or solid matrix having a concentration of halogenated organiccompounds from 10 ppm to 300,000 ppm under agitating at a preselectedreaction temperature. The agitation of the resulting mixture isimportant to achieve the best results when the aforementioned reagenthas been introduced into the contaminated matrix, especially whenrelatively low concentration of halogenated contaminants, usually lessthan 500 ppm, is initially present. It is desirable to carry out thedecontamination reaction under an ultrasonic condition. The use ofultrasound in the decontamination process can increase 10-15% ofreaction efficiency and decrease 20-25% of decontamination time atleast. The use of UV radiations, electric fields and/or microwaves wasalso found to be advantageous.

The reaction between the aforementioned reactants and halogenatedorganic compound can be performed in the presence or the absence of air.If desired, the reaction can be run in the presence of an inert gas suchas nitrogen. In the practice of the present invention, the relativelyhigh water content of the contaminated matrix has no adverse effect onthe reactivity of the decomposition reagent of the present invention.

It has been found that the order of the decomposition process is notconsiderably critical. Thus, the non-alkali metal, polyalkyleneglycol/orNixolens® and hydroxide/or alcoholate can be simultaneously or in acertain sequence added to the contaminated matrix. However, the methodcan be practiced otherwise, for example, the contaminated matrix may beadded to the mixture of a non-alkali metal and a polyalkyleneglycol/or aNixolens®, while or prior to adding of a hydroxide/or an alcoholate.

As a practical matter, using the non-alkali metal in the decompositionreagent can avoid using specialized equipment and special materialhandling procedures involved in the use of metallic sodium and oxidizingagents such as sodium peroxide, or other sources of free radicals. Afterthe reaction, unconsumed metals precipitate to the bottom of the reactortogether with the unconsumed polyalkyleneglycol/or Nixolens® andhydroxide/or alcoholate, and can be readily decanted from the fluiddecontaminated. It has also been found that the decontaminationeffectiveness is largely enhanced by introducing the non-alkali metalinto the decomposition reagent instead of oxidizing agents disclosed inour previous art methods, such as sodium peroxide.

Especially, the reagent of the present invention can also be combinedtogether with some solid carriers having a certain particle size anddistribution, to become an immobilized bed for continuously removinghalogenated organic compounds from contaminated fluids. For example,this continuous process is suitable for the decontamination treatment ofprocessing dielectric fluids without interrupting the operation of theelectrical apparatus containing the fluid to be processed.

The solid carriers which can be used in the practice of the presentinvention are calcium oxide, magnesium oxide, granular aluminium, pumicestone, perlite, diatomite, alkali or alkaline earth metal carbonate andbicarbonate etc. These particles can have a size range of 0.1-10 mmdiameter.

Solid carriers can be added to the mixture of a non-alkali metal, apolyalkyleneglycol/or an alkene oxide copolymer and a hydroxide/or analcoholate in the presence of a solvent, such as alcohol, which then canbe removed by evaporation and filtration. Alternatively,polyalkyleneglycols/or alkene oxide copolymers can be added to solidcarriers, and mixed under a mild heating (generally lower than 40° C.)so as to get polymers well distributed to solid carriers. The non-alkalimetal and hydroxide/or alcoholate are added to this mixture understirring, and then cooling to room temperature. More simply, solidcarriers, non-alkali metal, polyalkylene glycol/or alkene oxidecopolymers and hydroxide/or alcoholate can be mixed together in ablender to give a powder or a slurry at room temperature.

The reagents above formed are used to fill a certain device with anappropriate form and size according to the particular applicationconcerned, so as to form an immobilized bed such as a column and acartridge. Particularly the reagents can be added to the contaminatedfluid and pass through a filter to form a porous layer on the septum ofthe filter to become a filter aid. The filter aid formed in such way isnot only a filtering medium which traps the solids from the fluid to betreated, but also gives a decomposition of halogenated organic compoundsfrom the contaminated fluid. The contaminated fluid is continuouslypassed through the immobilized bed, and this process is a single run orseveral repeated runs in an open or closed system according to thecontaminated level and type of the fluid to be treated. Generally, fortransformer oils contaminated by PCBs, the decontamination temperaturecan range from 20° C. to 150° C.

In order to effectively monitor the decontamination process, a HewlettPackard Mod. 5890A gas chromatograph with an Ni63 electron capturedetector (GC/ECD) is typically used to analyze the halogenated compoundcontent. For example, polychlorinated biphenyls are analyzed by GC/ECDunder the following conditions: HP Ultra 2 capillary column packed withcross-linked 5% phenyl methyl silicone gum; injector temperature: 270°C.; detector temperature: 330° C.; column temperature: from 50° C. to130° C. at the rate of 40° C./min, then 130° C. to 290° C. at the rateof 2.5° C./min; carrier gas: helium; make up gas: argon containing 5weight percent methane. The concentration of PCBs in the sample iscalculated by DCMA method (Dry Color Manufacture's Association), and IECMethod (International Electrochemical Commission) proposed by TC10/WG7which can identify and quantify the individual (or groups of) congeners.Further, DEXSIL Inc.L2000™ PCB-chloride electrochemical-analyzer can beused for on-site monitoring of the decontamination process at theindustrial application, such as mobile decontamination plant.

The following examples further illustrate the invention.

EXAMPLE 1

100 g of clean hydrocarbon-based transformer oil containingapproximately 700 parts per million (ppm) of PCBs, was heated to 100° C.in a three-neck flask fitted with an agitator a and a condenser.Thereafter, 0.51 g of aluminium powder, 4.53 g of Nixolens® VS-13 havinga molecular weight of about 1000 and 1.89 g of potassium hydroxide inpowder form were added to the contaminated oil. The reaction vesselcontents were stirred vigorously and maintained at 100° C. throughoutthe run. Oil samples were periodically taken for PCB analysis. The PCBcontent was reduced from 700 ppm to less than 2 ppm in 20 minutes.

EXAMPLE 2

The procedure of Example 1 was repeated except the use of ultrasound(ultrasonic intensity, 12.5 Wcm⁻² ; ultrasonic frequency, 1 Mhz). After15 minutes, no detectable PCBs was found in the oil sample.

EXAMPLE 3

100 g of transformer oil containing 8764 ppm of polychlorinatedbiphenyls was poured into the reaction vessel as indicated in Example 1and heated to 100° C. 1.7 g of aluminium powder, 30.4 g of Nixolens®VS-13 and 16.5 g of potassium hydroxide were added to the vessel. Thereaction vessel contents were agitated and maintained at 100° C. Thereaction was carried on for 15 minutes and the oil sample was withdrawnfor PCB analysis by IEC method (International ElectrotechnicalCommission, TC10/WG79 which can identify and quantify individual (orgroups of) congeners with PCB congener 30 and 209 as reference peaks forthe determination of their Experimental Relative Retention Times (ERRT)and Experimental Relative Response Factors (ERRF). As shown in Table 1,the PCB content was reduced from 8764 ppm to 24 ppm in 15 minutes.

                  TABLE 1                                                         ______________________________________                                        PCB               ppm (min)                                                   (N. IUPAC)        0'       15'                                                ______________________________________                                        5 8               --       7.1                                                15 18             --       6.1                                                17                --       1.2                                                16 32             --       1.8                                                26                --       1.7                                                31                 8.8     2.3                                                28                12.4     --                                                 20 21 33 53       --       0.1                                                39 52 69 73       34.4     4.3                                                44                --       0.2                                                70 76 96           8.9     --                                                 66 80 88 93 95 102                                                                              318.3    --                                                 92                52.4     --                                                 84                22.2     --                                                 89 90 101         315.7    --                                                 79 99 113         11.3     --                                                 86 97 152         16.1     --                                                 81 87 111 115 116 39.9     --                                                 120 136 148       212.5    --                                                 77 110            197.0    --                                                 151               346.8    --                                                 106 123 149       993.0    --                                                 118 139 140       56.5     --                                                 134 143           38.9     --                                                 114               10.5     --                                                 146 161 165 188   124.6    --                                                 132 153 184       948.7    --                                                 105 127 168       173.7    --                                                 141               152.1    --                                                 179               130.6    --                                                 137 176           49.0     --                                                 138 160 163 164   771.3    --                                                 158 186           54.4     --                                                 126 129 178       95.4     --                                                 166 175           34.9     --                                                 159 182 187       305.4    --                                                 162 183           176.9    --                                                 128               54.2     --                                                 167               23.6     --                                                 185               47.5     --                                                 174 181           539.3    --                                                 177               219.0    --                                                 156               133.7    --                                                 201               92.6     --                                                 204               113.3    --                                                 172 192 197        6.8     --                                                 180               902.8    --                                                 193               52.1     --                                                 191               14.7     --                                                 200               21.3     --                                                 170 190           339.0    --                                                 198                7.4     --                                                 199               134.5    --                                                 196 203           91.7     --                                                 189                7.0     --                                                 195 208           81.6     --                                                 194               136.9    --                                                 205               10.3     --                                                 206               22.5     --                                                 TOTAL             8764.4   24.9                                               ______________________________________                                    

Table 1 shows that most of PCB congeners found in the initialcontaminated oil were destroyed by the reaction with our reagentcomposed of aluminium powder,(Nixolens® VS-13 and potassium hydroxide inonly 15 minutes.

EXAMPLE 4

The procedure of Example 1 was repeated except that the hydroxide was2.01 g of potassium tertbutylate. The PCB content was reduced from 700ppm to less than 2 ppm in 30 minutes.

EXAMPLE 5

In order to illustrate the effect of the non-alkali metal of the presentinvention, a series of comparative tests was conducted employing anon-capped polyalkylene glycol alkyl ether and alkali metal hydroxidereagent system proposed by Brunelle in U.S. Pat. No. 4,353,793.

To the three-neck flask 1 as described in example 1 there were added:100 g of clean transformer oil containing 646 ppm of PCBs, 2.04 gpowdered potassium hydroxide and 3.54 g of polyethylene glycolmonomethyl ether having an average molecular weight 350 (PEGM350).Meanwhile there were added to the second volume of such contaminatedtransformer oil, 0.51 g aluminium powder, 1.53 g powdered potassiumhydroxide and 3.53 g PEGM350 in the reaction flask 2 same as flask 1.Both flask contents were agitated with a speed of 600 rpm and kept at100° C. throughout the run. The reactions proceeded for about 2 hoursand the oil samples were withdrawn periodically for PCB analysis. ThePCB analysis results are presented in Table 2.

                  TABLE 2                                                         ______________________________________                                                     PCB (ppm)                                                        Reaction Time (min)                                                                          KOH/PEGM350 Al/KOH/PEGM350                                     ______________________________________                                         0             646         646                                                15             88          2                                                  30             49          0                                                  60             20          0                                                  120             8          0                                                  ______________________________________                                    

The above results show that the PCB contents were reduced from 646 ppmto 2 ppm with the Al/KOH/PEGM350 reagent in only 15 minutes, while thesame removal of PCB's with the KOH/PEGM350 reagent required 2 hours.

EXAMPLE 6

Another series of comparisons between the use of the Na₂ O₂ /K₂ CO₃/Carbowax 6000 reagent disclosed in our previous U.S. Pat. No. 4,632,742and the use of Al/KOH/Carbowax 6000 reagent of the present invention wasmade to determine the effectiveness of these reagents to remove PCB fromnon-polar organic solvents.

There was respectively added 100 g of transformer oil contaminated with560 ppm of PCBs to flask 1 and flask 2 as described in example 1. 0.58 gof sodium peroxide, 3.04 g of potassium carbonate and 4.58 g of solidCarbowax polyethyleneglycol (average M.W. 6000) were added to flask 1.Meanwhile 0.52 g aluminium powder, 3.06 g powdered potassium hydroxideand 4.55 g Carbowax 6000 were added to the flask 2. Each flask contentswere agitated and kept at 100° C. throughout the run. Reaction proceededfor 2 hours and samples were taken periodically for PCB analysis. Theresults obtained are shown in the following Table 3.

                  TABLE 3                                                         ______________________________________                                                 ppm PCB                                                              Time       Carbowax6000/                                                                             Carbowax6000/                                          (min)      K.sub.2 CO.sub.3 /Na.sub.2 O.sub.2                                                        KOH/Al                                                 ______________________________________                                         0         560         560                                                    30         207         68                                                     60         159         48                                                     120        105         13                                                     ______________________________________                                    

Table 3 indicates that the Al/KOH/PEG reagent is a more effectivereagent for the elimination of PCB contaminants than the Na₂ O₂ /K₂ CO₃/PEG reagent.

EXAMPLE 7

Further, a series of comparative tests was performed employing theDMSO/KOH/PEG reagent system as described by Peterson in U.S. Pat. No.4,532,028.

There were added 2.02 g powdered potassium hydroxide, 3.57 gpolyethylene glycol having an average molecular weight of 600 (PEG600)and 1 ml DMSO to 100 g of transformer oil containing approximately 600ppm of PCB in flask 1. Meanwhile, in flask 2, 2.01 g powdered potassiumhydroxide, 3.50 g PEG 600 and 0.44 g aluminium powder were added to thesecond volume of the transformer oil contaminated with the same PCB's asthe oil in flask 1. The flask 1 and flask 2 were the same reactionvessels as indicated in Example 1. Both reactor contents were agitatedand kept at 90° C. throughout the run. The reactions were carried on for2 hours and oil samples were withdrawn periodically for PCB analysis.The results are presented in Table 4:

                  TABLE 4                                                         ______________________________________                                        Reaction Time                                                                             ppm PCB                                                           (min)       KOH/PEG600/DMSO                                                                             Al/KOH/PEG600                                       ______________________________________                                         0          600           600                                                 15          --            175                                                 20          219           --                                                  30          143           74                                                  60           66           31                                                  ______________________________________                                    

EXAMPLE 8

In order to illustrate the effect of different non-alkali metals on theprocess of present invention, a series of reactions was performed. Inone reaction vessel as described in Example 1, there were added 0.54 byweight of aluminium powder, 1% by weight of potassium hydroxide powderand 3% by weight of PEGM350 to 100 g of transformer oil containingapproximately 600 ppm of PCBs. The resulting heterogeneous mixture wasstirred and maintained at 95° C. The reaction proceeded for 15 minutesand the oil was removed and analyzed for PCB content.

The above procedure was repeated employing calcium, iron, magnesium,manganese, nickel, tin, silicon and zinc respectively. The results arepresented in Table 5.

                  TABLE 5                                                         ______________________________________                                        Metal (wt %)                                                                           PEGM350 (wt %)                                                                              KOH (wt %)                                                                              % Reaction                                   ______________________________________                                        Al (0.50)                                                                              3.11          1.07      95.1                                         Ca (0.50)                                                                              3.03          1.02      83.2                                         Fe (0.58)                                                                              3.08          1.06      81.7                                         Mg (0.53)                                                                              3.03          1.06      94.5                                         Mn (0.54)                                                                              3.09          1.03      93.3                                         Ni (0.51)                                                                              3.04          1.06      85.5                                         Sn (0.57)                                                                              3.03          1.07      81.3                                         Si (0.53)                                                                              3.00          1.06      92.8                                         ______________________________________                                    

EXAMPLE 9

To an Erlenmeyer flask with a magnetic stirrer/hot plate system, therewas added 10 grams of sludge contaminated with Cl.sub.(1-4)--C.sub.(1-4) -alkylbenzene 22.4 mg/g), BrCl.sub.(1-2) --C.sub.(1-3)-alkylbenzene (0.2 mg/g), Br--C₃ -alkylbenzene (0.2 mg/g), Cl.sub.(3-5)-biphenyl (3.9 mg/g) and Cl₆ -benzene (<0.01 mg/g), which was providedby Center For Industrial Research of Oslo in Norway. 19.89 g ofdiethylene glycol was added to the flask and heated to about 85° C. 0.62g of aluminium powder and 4.28 g of powdered potassium hydroxide wereadded to the flask while the flask contents were stirred. The reactioncontents were agitated for 20 hours and the temperature was kept at 85°C. Following the reaction, the flask contents were filtrated and thesludge was air-dryed and submitted for the analysis of halogenatedorganic compound content. The analysis results showed that there was nodetectable halogenated organic compounds found in the sludge.

EXAMPLE 10

6.77 g Carbowax 6000, 0.26 g aluminium powder, 5.90 g potassiumhydroxide and 31.37 g pumice-stone (PUMEX ; from LIPARI island, Italy)were mixed in a blender for 1 minute, and then charged into a column (20mm, h 280 mm) thermostated at 85° C. 102.97 g of mineral oil containing816 ppm of PCB passed through the column at a flow rate of 65 ml/h. Theeffluent oil from the column was collected in a clean vessel. After onecycle, the oil sample was taken for PCB analysis, and the analysisresult indicated that the PCB content had been reduced to 8.8 ppm.

While certain representive embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in this art that various changes and modifications may be madetherein without departing from the scope of the invention.

I claim:
 1. A process for the decomposition of a halogenated compoundwhich comprises subjecting a fluid or solid matrix contaminated withsaid halogenated compound to a reagent consisting of (a) at least onenon-alkali metal selected from aluminum, calcium, iron, magnesium,manganese, nickel, palladium, silicon, tin, titanium and zinc; (b) analkali or alkaline earth metal hydroxide or an alkali or alkaline earthmetal C₁ -C₆ alcoholate; and (c) a polyalkylene glycol or a randomcopolymer of ethylene and propylene oxides; and stirring at atemperature from ambient to 200° C.
 2. A process according to claim 1 inwhich the halogenated compound is PCB, PCDD, PCDF, DDT, or DDE.
 3. Aprocess according to claim 1 in which the mole ratio by saidpolyalkylene glycol or random copolymer of ethylene and propylene oxidesto the halogen of said halogenated compound is 1:1 to 30:1; the moleratio of said hydroxide or alcoholate to said halogen is 10:1 to 200:1;and the non-alkali metal is present in about 0.02-5.0% by weight of thecombined weight of the matrix and reagent.
 4. A process according toclaim 1 in which the non-alkali metal is aluminum or a mixture thereofwith titanium.